How to use the Terrain Transparency?

I tried to use the

http://wiki.unity3d.com/index.php/TerrainTransparency

But the information the link is giving is kind of short.
I just want to make part of my terain invisible (The terrain has only 1 texture).

I have a specific question, I made a new shader with the shader code, what should I do with it? Just leave it in the Assets Library?

Anyway, could somone give me a more detailed explanation on how to make it work?

Thanks in Advance!

-Dan

No Dear,
You must create a material and put the shader there. Then move the material to the terrain. It makes the terrain transparent but it will not cast any shadows!!!